KVM: x86/mmu: fix memoryleak in kvm_mmu_vendor_module_init()

When register_shrinker() fails, KVM doesn't release the percpu counter
kvm_total_used_mmu_pages leading to memoryleak. Fix this issue by calling
percpu_counter_destroy() when register_shrinker() fails.

Fixes: ab271bd4 ("x86: kvm: propagate register_shrinker return code")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Link: https://lore.kernel.org/r/20220823063237.47299-1-linmiaohe@huawei.com
[sean: tweak shortlog and changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>

arch/x86/kvm/mmu/mmu.c

@@ -6702,10 +6702,12 @@ int kvm_mmu_vendor_module_init(void)
 
 	ret = register_shrinker(&mmu_shrinker, "x86-mmu");
 	if (ret)
-		goto out;
+		goto out_shrinker;
 
 	return 0;
 
+out_shrinker:
+	percpu_counter_destroy(&kvm_total_used_mmu_pages);
 out:
 	mmu_destroy_caches();
 	return ret;